I have two favorites. They make me feel all warm and fuzzy.
Rev. Norb (Boris the Sprinkler) on Jenny Jones:
http://www.youtube.com/watch?v=QQF5KhbtDCA
Joey Ramone and his mommy on Geraldo. She was always so cute.
http://www.youtube.com/watch?v=g1Fo1_ZV7CY
Honorable mention: GG Allin's many, many appearances. Here's one:
http://www.youtube.com/watch?v=B-hR9G1ZO6Q